Wallboard adaptor brackets have long been used to grip wallboard around openings so that wall plates or other devices can be secured to the wall. One type is simply a rear bracket which is secured to the wall plate by screws going through the wallboard. Another, shown in FIG. 1, is a rectangular bracket with an opening in it which is held to the wallboard by retaining pawls secured to the bracket by screws and pressing against the inner surface of the wallboard. This is relatively expensive to manufacture because it requires that a keeper be formed in the bracket to hold the retaining screws perpendicular to the bracket. My invention eliminates the need for this keeper.